Did you know… that Reykjavík is a city of geothermal energy? Did you know that the city of...
Propylitic Alteration
A term borrowed from studies of hydrothermal ore deposits that refers to an assemblage of secondary hydrothermal minerals which forms in igneous rocks. This assemblage is made up of chlorite, illite, feldspar (both Na and K-rich varieties), epidote, calcite and pyrite, imparting a dark green tint to the appearance of altered rocks. It is commonly developed in volcanic-plutonic sequences that host high-temperature geothermal reservoirs.
Geothermal Glossary
Word of the Week – Vadose Zone
Vadose Zone A hydrogeological term that represents the volume of rock and unconsolidated materials between the ground surface and the underlying water table, in which pores and cracks are filled or partially filled with air.
Word of the Week – Vapor-Dominated Reservoir
Vapor-Dominated Reservoir he highest grade of geothermal resource in which self-flowing wells produce dry steam from a reservoir containing a mixture of hot water and steam. Larderello, Italy and The Geysers, California, USA are examples, and they are extremely...
Word of the Week – Wairakite
Wairakite A zeolite mineral of hydrothermal origin that was first identified in the Wairakei geothermal field in New Zealand by Alfred Steiner. It forms clear to white prismatic crystals, which have a distinctive cross hatched twinning, and it is commonly associated...